1. Field of the Invention
This invention relates generally to weaving looms of various kinds and relates particularly to mechanisms for operating the lay of a loom to beat up the weft thread in either a shuttle type loom or a shuttleless type loom.
2. Description of the Prior Art
Heretofore weaving looms have been provided with a lay mounted on spaced swords which were adapted to be oscillated by the loom power plant in timed relationship with other elements of the loom. The lay has included a bed for supporting a weft thread carrying device as such device is driven from end to end of the bed by picker sticks, torsion bars, springs, or other mechanisms and such lay also has included a reed or comb which beats up the weft thread that had been placed in the shed of the warp threads by the weft thread carrying device. Due to the mass of the lay and the speed of the picker sticks or other driving mechanism, such lay normally has been in substantially constant motion back and forth while the weft thread carrying device has been driven from end to end thereof. The constant banging, jerking, and slapping movements have created substantial vibration and noise and when a large number of looms have been in operation in a weaving room the noise level has been sufficiently intense to be detrimental to humans working therein.
Some efforts have been made to provide linkages for driving the lay of a loom so that the lay remains in a substantially fixed or dwell position during a portion of the rotation of a drive crank to permit the weft thread to be transferred from one end of the lay to the other by a shuttle, missile, rapier or other weft thread carrying device and such lay is advanced and retracted during another portion of the rotation of the crank. However, it has been difficult to provide a dwell of greater than approximately 180.degree. of rotation of the crank without using a cam. Some examples of prior art linkages are the patents to Baker 1,683,324 and 1,970,832; Breddin et al 2,004,306; Shimwell 2,382,511 and 2,471,354; and Costa Font 3,110,327.